Prior to coaching Nebraska and Oakland Raiders, Callahan was one of game's best line coaches with stops including Philadelphia and the University of Wisconsin.
Mangini listened to the suggestion of Tannenbaum, and the rest is history.
And many feel the addition of Callahan was one of the Jets best off-season moves.
Not only will Callahan help the Jets offensive line, but their offense overall.
"What I like about Bill is he's incredibly flexible," said Mangini. "He's got the West Coast experience; he's got the coordinator experience; he's got the head coaching experience, and he's called plays."
And Callahan's myriad experience has already paid dividends with the Jets offensive linemen throughout this off-season.
"He's able to give those guys a real insight into the why's - why we're running this blocking scheme; why the hot (read) is where it is; what we have to do on each play and how it fits into the quarterback's depth," said Mangini.
Callahan is one of the smartest offensive minds around, and his attention to detail should really rub off on his Jets line.
"He can give a lot more detail because he has a great understanding of the big picture," said Mangini.
And for the Jets big picture, this hiring could turn into a masterstroke.